Getting to know your ADHD brain: The prefrontal cortex and why intention doesn’t always lead to action

When people talk about ADHD and the brain, the conversation often turns to something called executive function. It’s one of those terms that sounds neat and tidy on paper, but in reality it can feel a bit abstract – and, if I’m honest, it has always conjured up slightly unhelpful images for me of briefcases and men in suits.

But if we’re going to understand what’s happening in ADHD, it’s worth spending a bit of time here, because this idea of executive function is closely tied to a part of the brain called the prefrontal cortex – often shortened to PFC.

If you picture the brain, the PFC sits just behind the forehead. It plays a central role in helping you to organise behaviour in a way that lines up with your goals. This includes things like planning, prioritising, decision-making, impulse control and follow-through.

In other words, it’s not just about knowing what to do; it’s about being able to do it.

When knowing doesn't lead to doing

In ADHD, the PFC doesn’t always engage as consistently or efficiently as needed. That’s an important distinction. It’s not a question of ability or understanding, but of activation – getting the system online in the moment and keeping it there.

In everyday life, this might show up in a familiar way. You know exactly what needs to be done but you can’t seem to start. Or you begin something with good intentions, only to lose direction partway through. It can feel confusing, especially when, on some level, the knowledge is there.

This is where the PFC’s role in working memory comes in. Working memory allows you to hold and work with information in the short term – keeping track of steps, sequencing actions and staying orientated towards a goal. When this system is under strain, tasks can quickly start to feel unclear or overwhelming, even if they seemed manageable at the outset.

Emotional regulation

The PFC is also closely involved in emotional regulation. It helps to modulate input from emotional centres in the brain – including the amygdala – allowing you to pause, reflect and respond in a more measured way. When the PFC is less active, which can happen under stress or fatigue, those emotional signals can come through more strongly and more quickly, making reactions feel harder to manage or contain.

Another important piece of the puzzle is that the PFC is highly sensitive to context. It doesn’t operate in a fixed way. Things like stress, tiredness or low interest can reduce its effectiveness, while clarity, structure and meaningful motivation can help it engage more reliably.

This helps to explain why certain strategies can make such a difference. Breaking tasks into smaller defined steps, using external reminders or creating simple routines are not just organisational tools; they are ways of supporting the PFC to stay active and connected to what you’re trying to do.

Seen in this light, these approaches aren’t “workarounds” or signs that something is missing. They’re practical ways of working with how the brain functions, rather than against it.

Adding another layer

Understanding the role of the PFC adds another layer to how we think about ADHD. It shifts the focus away from ideas like motivation or effort and towards something more specific: how consistently the brain can access and sustain the systems that turn intention into action.

It also highlights something important: the gap between knowing and doing isn’t a personal failing; it’s a reflection of how this part of the brain is functioning in that moment. And, as with the cerebellum (see the previous article), the PFC doesn’t work in isolation. It is constantly interacting with other parts of the brain, particularly those involved in emotion.

In the next article, we’ll explore the amygdala – and how emotional intensity can sometimes override even the best-laid plans.

Note: This article is for information only and isn’t a substitute for personalised medical or psychiatric advice or treatment. The ideas and suggestions here draw on a mix of clinical experience and emerging research, which means our understanding is still developing and not every approach will be right for every person with ADHD. Please treat anything you try as an experiment, ideally alongside the help and support of a qualified, neurodivergent-aware professional like myself.

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